Document Type

Thesis - Open Access

Award Date

2020

Degree Name

Master of Science (MS)

Department / School

Dairy Science

First Advisor

Srinivas Janaswamy

Keywords

Beads, Biopolymers, Nitrates, Phosphates, Sodium alginate, Water purification

Abstract

Nitrates and phosphates are essential nutrients for plants growth. Their excess presence in water, however, could cause eutrophication affecting the water quality and altering the aquatic ecosystem. Algal blooms and the presence of toxins such as microcystin in freshwater bodies are hazardous to humans, animals, and wildlife. Conventional technologies such as ion exchange, distillation, reverse osmosis, and bioreactors aid immensely to remove nutrients; however, they are expensive. Furthermore, building new nitrate and phosphate treatment units, maintenance and post-disposal are costly too. In this regard, there exists an unmet need for alternative processes that are renewable and cost-effective to treat contaminated water. Herein, a novel opportunity based on inexpensive and widespread polysaccharides, e.g. alginate, has been developed to capture nitrate and phosphate from water and improving water quality. Alginate beads have been prepared in the presence of divalent (Ca2+, Fe2+, Ni2+, Cu2+, Zn2+, and Sr2+) and trivalent (Al3+ and Fe3+) cations. The maximum absorption capacity of nitrate and phosphate by the alginate beads has been established using 5, 10, 25 mg/L of nitrate and 1, 5, 10, 15, and 20 mg/L of phosphate solutions. Results suggest that alginate beads are effective to capture nitrate and phosphate from solutions and the type of ionic crosslink ions has a significant influence on the total absorbed amount. A maximum (94.0 ±0.1)% of phosphate could be removed using the Al3+-alginate beads and (33.6±1.9)% of nitrates by the Fe3+-alginate beads. Further characterization of beads by FTIR and DSC reveal the influence of ions on the nitrate and phosphate absorption capacity by the alginate beads. Overall, this study successfully establishes the potential of polysaccharide beads to capture nutrients and improve water quality and opens a new window of opportunities to water treatment technologies.

Library of Congress Subject Headings

Water -- Purification.
Alginates.
Nitrates.
Phosphates.
Polysaccharides.
Biodegradation.

Format

application/pdf

Number of Pages

87

Publisher

South Dakota State University

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Included in

Food Science Commons

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Rights Statement

In Copyright